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Self-sensitized photo-oxidation of platinum(II) complexes of 1,10-phenanthroline with 3,4-dimercaptoluene and thiosalicylic acid 1O2 (S. Shukla, S. S. Kamath and T. S. Srivastava, J. Photochem. Photobiol. A; Chem., 50 (1989) 199–207) — a reply
J. Photochem.
Photobioi. A:
Chem.,
56
(1991)
397
397
Self-sensitized photo-oxidation of platinum(I1) complexes of l,lO-phenanthroline with 3,4-dimercaptotoluene and thiosalicylic acid by ‘02 (S. Shukla, S. S. Kamath and T. S. Srivastava, J. Photochem. Photobiol. A: Chem., 50 (1989) 199-207) - a comment Swapan K. Bose, Utpal Das and Biswajit Sarkar Deparrment
of Chemistry, University Calcutta 700 009 {India)
(Received
College
of Science, Universiy of Calcutta, 92 A.P.C.
Road,
July 31, 1990)
The quenching rate constant Ko for photo-oxidation azide was determined in ref. 1. The following relationship
(- WlWo ( - WlWo
_
l
-’
_
Krtsl
&IQ1
c
of [Pt(phen)(DMT)] by sodium (eqn. (4) in ref. 1) was obtained
Kd
KdQl
and sodium azide respectively where [S] and [Q] are the concentrations of [Pt(phen)(DMT)] and Kd and K, are the rates of decay of IO2 and chemical quenching of ‘02 respectively. The subscripts Q and 0 denote the presence and absence of the quencher, sodium azide. The left-hand side of this equation has been plotted against [S] in Fig. 4 and the intercept of the straight line so obtained has been set equal to K,/Ko[Q]. However, the intercept in Fig. 4 is negative, whereas all three terms in K,/K,[Q] are positive. In addition, the straight line has been extrapolated through the negative region of the ordinate, but there is no experimental data point in that region. Moreover, the occurrence of any such point would mean that the rate of photo-oxidation is faster in the presence of the quencher. Therefore this extrapolation is clearly inappropriate. ThirdIy, the three data points at lower concentrations (1.0-1.5X 10m4 M) of [Pt(phen)(DMT)] clearly have a slope much less than that of the straight line drawn. For these reasons, the quenching rate constant Ko cannot be obtained by this method. 1 S. Shukla, 199.
S. S. Kamath
lOlO-6030/91/$3.50
and T. S. Srivastava,
J. Photochem. Photobiol. A: Chem., 50 (1989)
0 Elsevier
Sequoia/Printed
in The Netherlands
Photobioi. A:
Chem.,
56
(1991)
397
397
Self-sensitized photo-oxidation of platinum(I1) complexes of l,lO-phenanthroline with 3,4-dimercaptotoluene and thiosalicylic acid by ‘02 (S. Shukla, S. S. Kamath and T. S. Srivastava, J. Photochem. Photobiol. A: Chem., 50 (1989) 199-207) - a comment Swapan K. Bose, Utpal Das and Biswajit Sarkar Deparrment
of Chemistry, University Calcutta 700 009 {India)
(Received
College
of Science, Universiy of Calcutta, 92 A.P.C.
Road,
July 31, 1990)
The quenching rate constant Ko for photo-oxidation azide was determined in ref. 1. The following relationship
(- WlWo ( - WlWo
_
l
-’
_
Krtsl
&IQ1
c
of [Pt(phen)(DMT)] by sodium (eqn. (4) in ref. 1) was obtained
Kd
KdQl
and sodium azide respectively where [S] and [Q] are the concentrations of [Pt(phen)(DMT)] and Kd and K, are the rates of decay of IO2 and chemical quenching of ‘02 respectively. The subscripts Q and 0 denote the presence and absence of the quencher, sodium azide. The left-hand side of this equation has been plotted against [S] in Fig. 4 and the intercept of the straight line so obtained has been set equal to K,/Ko[Q]. However, the intercept in Fig. 4 is negative, whereas all three terms in K,/K,[Q] are positive. In addition, the straight line has been extrapolated through the negative region of the ordinate, but there is no experimental data point in that region. Moreover, the occurrence of any such point would mean that the rate of photo-oxidation is faster in the presence of the quencher. Therefore this extrapolation is clearly inappropriate. ThirdIy, the three data points at lower concentrations (1.0-1.5X 10m4 M) of [Pt(phen)(DMT)] clearly have a slope much less than that of the straight line drawn. For these reasons, the quenching rate constant Ko cannot be obtained by this method. 1 S. Shukla, 199.
S. S. Kamath
lOlO-6030/91/$3.50
and T. S. Srivastava,
J. Photochem. Photobiol. A: Chem., 50 (1989)
0 Elsevier
Sequoia/Printed
in The Netherlands